Dear [Name],
I am writing this letter to extend my sincere apologies for [reason for apology]. I understand that my actions have caused you and your team an inconvenience, which was entirely unintentional. Nonetheless, I take full responsibility for my actions, and I pledge to make it right to the best of my ability.
Explanation
I would like to take this opportunity to explain what happened, to give you a better understanding of the situation. [Explain what happened and why]. This incident was a result of [mention the cause], which was entirely out of my control. However, I should have informed you and your team about this situation, and I now regret not doing so in a timely manner.
Impact
I understand how much this incident may have impacted your business and caused you significant trouble. Please accept my apologies for any inconvenience, stress, or financial burden that my actions caused. It was never my intention to cause any harm, and I will do everything within my power to make things right.
Action
I would like to assure you that I have taken measures to avoid a recurrence of this incident. Moving forward, I will [mention what you will do to prevent this from happening again].
In an effort to rectify the situation, I would also like to propose that [mention any proposals or solutions you have come up with to make it right].
Conclusion
Finally, I would like to apologize once again for this unfortunate situation and the trouble and inconvenience it has caused you. I value our relationship and would like to assure you that I remain committed to finding a solution to any issue that arises. Should you have any further concerns or queries, please do not hesitate to contact me, and I will be more than willing to address them.
Thank you for taking the time to read this, and I look forward to hearing from you soon.
Sincerely,
[Your name]